The primary objective is to identify cell surface materials which are associated with human malignant lymphoproliferative disorders and to isolate these materials in large quantities so that their chemical structures such as amino acid sequence, can be determined and so that they can be used to induce immune response. Cultured as well as noncultured human malignant cells will be used to isolate the leukemia-lymphoma associated antigens (LLAA). We have recently detected antigen(s) common to several cultured human malignant T cell lines by the use of a sensitive radioimmunoassay involving I125-labeled antibody to human malignant T cells (MOLT 4). All of these cell lines were derived from the lymphocytes of patients with leukemia. The use of cultured cells will allow us to isolate the LLAA in large quantities and further allow us to feed the cell with a complete complement of C14-amino acids so that we can isolate uniformly radiolabeled LLAA. The radiolabel marker on LLAA will greatly facilitate the chemical characterization, especially the amino acid sequence determination of LLAA. We will further attempt to isolate peptides which retain the tumor antigenicity, from the various digests of the uniformly C14-labeled and isolated LLAA. In another experiment, we radioiodinated MOLT 4 cells by the use of lactoperoxidase-catalyzed iodination and we are currently working on isolating the radioiodinated LLAA. In the present on-going project, we are detecting LLAA on cell by the combined use of the conventional complement-dependent cytotoxicity test and a sensitive radioimmunoassay. The use of the latter method may allow us to detect certain LLAA which will not be detected by conventional cytotoxic method. As the antisera, we have prepared baboon and rabbit antisera to noncultured lymphocytes from patients with acute lymphoblastic leukemia and lymphosarcoma cell leukemia.